CancerImmunol Immunother(1991) 34: 128-132 Short communication ~ ancer mmunolggy mmunotherapy © Springer-Verlag 1991 Seareh for the eritieal characteristics of phenotypieally different B cell lines, Burkitt lymphoma cells and lymphoblastoid cell lines, which determine differences in their functional interaction with allogeneic lymphocytes Javier Avila-Carifio, Sigurbjörg Torsteinsdottir, Barbro Ehlin-Henriksson, Maria G. Masucci, and Eva Klein Department of TumorBiology, KarolinskaInstitute, S-10401. Stockholm,Sweden Received27 February 1991/Accepted 23 July 1991 Summary. Burkitt lymphoma (BL) lines can be grouped according to phenotypic characteristics. Group I cells ex~ hibit the phenotype of resting B cells and grow as single cells. Such lines can be Epstein-Barr-virus(EBV)-negative or -positive. Group II and group III cells are always EBV- positive, they express B cell activation markers, grow in aggregates and resemble in varying degrees lymphoblas- toid cell lines (LCL). We studied three groups of BL lines for their capacity to interact with allogeneic lymphocytes. The results showed that as long as the lines have the group I phenotype, they do not stimulate allogeneic T lym- phocytes irrespective whether they can'y the EBV genome. The group II and IlI cells are stimulatory. Generally there was no correlation between sensitivity to lymphocyte-me- diated lysis and the phenotype of the lines. In one set of lines, the group I cells had higher sensitivity to both natural killer and lymphokine-activated killer effectors compared to the group II or III lines. However, such correlation could not be seen with the other two sets of lines. Among the phenotypic features investigated, expression of the adhe- sion molecules LFA-1 and LFA-3 correlated with the ten- dency for cell aggregation. Key words: B cell - Lymphocyte responses - Cytotoxic sensivity Introduction The two types of Epstein-Barr-virus(EBV)-infected B cells endowed with growth capacity in vitro, the lymphoblastoid cell lines (LCL) and the Burkitt-lymphoma(BL)-derived lines differ in many features. Polyclonal LCL can be estab- lished by explantation of B cells Dom healthy EBV- seropositive individuals, and by infecfing B cells in vitro with transforming strains of EBV. The cells of LCL have Offprint requests to: J. Avila-Carifio irregular shape, grow in aggregates and express activation markers (reviewed in [27]), nine EBV-encoded proteins (reviewed in [10, 25] and high levels of MHC class I antigens and leucocyte-adhesion molecules [l, 14, 15, 22]. They do not grow in nude mice when grafted subcu- taneously and do not clone in agarose; however, they grow in nude mice when implanted intracerebrally [20], and in SCID mice grafted subcutaneously [5, 16]. Newly explanted BL cells are monoclonal, and grow as singly dispersed uniformly round cells. [20, 27]. They share markers with the resting B cells in the germinal centers [7], they have no activation markers [27], and ex- press only one of the EBV-encoded proteins detected in the LCL, namely EBNA 1 [29]. They have a lower level of MHC antigen expression than the LCL, often showing relative differences between certain alleles [1, 15], and they have low levels of adhesion molecules on the plasma membrane [22]. They grow when injected subcutaneously into nude mice and clone better than LCL in agarose [20]. When propagäted in vitro the EBV-carrying, but not the EBV-negative BL cells usually change and acquire vari- able degrees of similarity with the LCL. Taking into con- sideration some of the characteristics listed above the BL lines are categorized as group I, II and III [27]. EBV-nega- tive BL lines and freshly explanted EBV-positive BL cells define the group I character. Group III is represented by cells that have marked similarities with LCL [27]. Acquisi- tion of LCLqike traits from groups I-III is imposed by the EBV genome. This is proven by the comparison of lines derived from EBV-negative and EBV-positive BL cells, and the sublines of originally EBV-negative BL cells con- verted in vitro by EBV [2]. Considerable effort has been directed to the analysis of the immune response against EBV and the various types of EBV-carrying B cells. Parallel studies of EBV-negative BL lines, EBV-carrying BL cells and LCL have made it possible to pose the questions: are EBV-carrying B cells, derived from lymphomas and normal lymphocytes, recog- nized differently by the effectors of cellular immunity? In what way does the presence of the EBV genome contribute to this recognition?